Comments on: Rhinovirus and zinc part 5: Magnesium is not the culprit http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/ About viruses and viral disease Sat, 11 Feb 2012 17:38:00 +0000 hourly 1 http://wordpress.org/?v=3.3.1 By: JST Books http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-26242 JST Books Thu, 21 Apr 2011 04:48:00 +0000 http://www.virology.ws/?p=2552#comment-26242 ffffggggggggggg ffffggggggggggg

]]> By: debtfreerevolution http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-21811 debtfreerevolution Fri, 18 Dec 2009 06:14:31 +0000 http://www.virology.ws/?p=2552#comment-21811 ProfVRR, you might want to check this one out re: research into zinc's effects on human and murine cells:<br><a href="http://scienceblogs.com/neurotopia/2009/12/zicam_and_your_nose.php" rel="nofollow">http://scienceblogs.com/neurotopia/2009/12/zica...</a> ProfVRR, you might want to check this one out re: research into zinc's effects on human and murine cells:
http://scienceblogs.com/neurotopia/2009/12/zica…

]]> By: profvrr http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-21813 profvrr Fri, 18 Dec 2009 03:55:57 +0000 http://www.virology.ws/?p=2552#comment-21813 When virology was simpler! I'm happy that they are online, because<br>they are gone from our library. When virology was simpler! I'm happy that they are online, because
they are gone from our library.

]]> By: l_a_s http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-21812 l_a_s Fri, 18 Dec 2009 03:54:28 +0000 http://www.virology.ws/?p=2552#comment-21812 Don't you love those 'old' virology papers in J. Bact! Don't you love those 'old' virology papers in J. Bact!

]]> By: profvrr http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-21814 profvrr Fri, 18 Dec 2009 00:48:26 +0000 http://www.virology.ws/?p=2552#comment-21814 Yes, I've seen that and similar papers. No genetic analysis was done<br>to prove the target of Zn inhibition, which is why I'm doing the<br>current experiments. In 1976 one could only make rather crude<br>conclusions about the target of Zn. For example, they say they have Zn<br>resistant mutants, but did not identify the mutation nor did they<br>provide little characterization. The fact that one Zn resistant mutant<br>no longer reacts with polyclonal anti-HRV sera tells me it was a<br>contaminant, probably poliovirus, which they also work with in that<br>paper. Yes, I've seen that and similar papers. No genetic analysis was done
to prove the target of Zn inhibition, which is why I'm doing the
current experiments. In 1976 one could only make rather crude
conclusions about the target of Zn. For example, they say they have Zn
resistant mutants, but did not identify the mutation nor did they
provide little characterization. The fact that one Zn resistant mutant
no longer reacts with polyclonal anti-HRV sera tells me it was a
contaminant, probably poliovirus, which they also work with in that
paper.

]]> By: debtfreerevolution http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-19365 debtfreerevolution Thu, 17 Dec 2009 22:14:31 +0000 http://www.virology.ws/?p=2552#comment-19365 ProfVRR, you might want to check this one out re: research into zinc's effects on human and murine cells:<br><a href="http://scienceblogs.com/neurotopia/2009/12/zicam_and_your_nose.php" rel="nofollow">http://scienceblogs.com/neurotopia/2009/12/zica...</a> ProfVRR, you might want to check this one out re: research into zinc's effects on human and murine cells:
http://scienceblogs.com/neurotopia/2009/12/zica…

]]> By: profvrr http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-19361 profvrr Thu, 17 Dec 2009 19:55:57 +0000 http://www.virology.ws/?p=2552#comment-19361 When virology was simpler! I'm happy that they are online, because<br>they are gone from our library. When virology was simpler! I'm happy that they are online, because
they are gone from our library.

]]> By: l_a_s http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-19360 l_a_s Thu, 17 Dec 2009 19:54:28 +0000 http://www.virology.ws/?p=2552#comment-19360 Don't you love those 'old' virology papers in J. Bact! Don't you love those 'old' virology papers in J. Bact!

]]> By: profvrr http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-19356 profvrr Thu, 17 Dec 2009 16:48:26 +0000 http://www.virology.ws/?p=2552#comment-19356 Yes, I've seen that and similar papers. No genetic analysis was done<br>to prove the target of Zn inhibition, which is why I'm doing the<br>current experiments. In 1976 one could only make rather crude<br>conclusions about the target of Zn. For example, they say they have Zn<br>resistant mutants, but did not identify the mutation nor did they<br>provide little characterization. The fact that one Zn resistant mutant<br>no longer reacts with polyclonal anti-HRV sera tells me it was a<br>contaminant, probably poliovirus, which they also work with in that<br>paper. Yes, I've seen that and similar papers. No genetic analysis was done
to prove the target of Zn inhibition, which is why I'm doing the
current experiments. In 1976 one could only make rather crude
conclusions about the target of Zn. For example, they say they have Zn
resistant mutants, but did not identify the mutation nor did they
provide little characterization. The fact that one Zn resistant mutant
no longer reacts with polyclonal anti-HRV sera tells me it was a
contaminant, probably poliovirus, which they also work with in that
paper.

]]> By: David Loria http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-19351 David Loria Thu, 17 Dec 2009 08:29:03 +0000 http://www.virology.ws/?p=2552#comment-19351 Actually, I just found this:<br>1. J Virol. 1976 Apr;18(1):298-306.<br><br>Inhibition by zinc of rhinovirus protein cleavage: interaction of zinc with<br>capsid polypeptides.<br><br>Korant BD, Butterworth BE.<br><br>Zinic ions rapidly inhibit virus production in HeLa cells infected with human<br>rhinovirus type 1A and lead to the accumulation of human rhinovirus type 1A<br>precursor polypeptides. The degree to which cleavage of these precursors is<br>inhibited is directly dependent on the quantity of cell-associated zinc.<br>Proteolysis resumes after the removal of zinc-containing medium, and the<br>accumulated viral precursors are cleaved predominantly to stable virus<br>polypeptides. The precursors stabilized at the lowest zinc levels are those that <br>contain capsid protein sequences. Furthermore, added zinc is bound to human<br>rhinovirus type 1A capsids and prevents them from forming crystals.<br>Zinc-resistant mutants display antigenic alterations in coat proteins. These<br>results suggest that zinc complexes with rhinovirus coat proteins and alters them<br>so that they cannot function as substrates for proteases or as reactants in the<br>assembly of the virus particles. Actually, I just found this:
1. J Virol. 1976 Apr;18(1):298-306.

Inhibition by zinc of rhinovirus protein cleavage: interaction of zinc with
capsid polypeptides.

Korant BD, Butterworth BE.

Zinic ions rapidly inhibit virus production in HeLa cells infected with human
rhinovirus type 1A and lead to the accumulation of human rhinovirus type 1A
precursor polypeptides. The degree to which cleavage of these precursors is
inhibited is directly dependent on the quantity of cell-associated zinc.
Proteolysis resumes after the removal of zinc-containing medium, and the
accumulated viral precursors are cleaved predominantly to stable virus
polypeptides. The precursors stabilized at the lowest zinc levels are those that
contain capsid protein sequences. Furthermore, added zinc is bound to human
rhinovirus type 1A capsids and prevents them from forming crystals.
Zinc-resistant mutants display antigenic alterations in coat proteins. These
results suggest that zinc complexes with rhinovirus coat proteins and alters them
so that they cannot function as substrates for proteases or as reactants in the
assembly of the virus particles.

]]> By: David Loria http://www.virology.ws/2009/12/16/rhinovirus-and-zinc-part-5-magnesium-is-not-the-culprit/comment-page-1/#comment-19349 David Loria Thu, 17 Dec 2009 01:16:55 +0000 http://www.virology.ws/?p=2552#comment-19349 Very interesting, it seems that Mg is enhancing plaque size by displacing Zn, and by increasing zinc concentration the equilibrium flips back reducing the plaques again. I would think that the effect is due to a cellular metalloprotease important for viral life cycle, but a minimum activity of this metalloprotease is necesary for cell survival as well. Under this conditions an extracellular quelating agent will flip the plaques back to small size in the presence of Zinc, indicating that the metalloprotease is membrane attached or extracellular, then you can use KO cell lines or specific inhibitors. If it is not extracellular (most likely due to the virus life cycle), then you will see accumulation of an unprocessed viral protein that might be spotted in a 2D gel (compare with and without Zg). Very interesting, it seems that Mg is enhancing plaque size by displacing Zn, and by increasing zinc concentration the equilibrium flips back reducing the plaques again. I would think that the effect is due to a cellular metalloprotease important for viral life cycle, but a minimum activity of this metalloprotease is necesary for cell survival as well. Under this conditions an extracellular quelating agent will flip the plaques back to small size in the presence of Zinc, indicating that the metalloprotease is membrane attached or extracellular, then you can use KO cell lines or specific inhibitors. If it is not extracellular (most likely due to the virus life cycle), then you will see accumulation of an unprocessed viral protein that might be spotted in a 2D gel (compare with and without Zg).

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